The White House on Wednesday dismissed a blog post by US investigative journalist Seymour Hersh alleging the United States was behind explosions of the Nord Stream natural gas pipelines, VOA reported.

"This is utterly false and complete fiction," said Adrienne Watson, a spokesperson for the White House National Security Council. Spokespeople for the CIA and State Department said the same.

Reuters also has not corroborated the report, published by Hersh, which said an attack was carried out last September at the direction of US President Joe Biden.

Sweden and Denmark, in whose exclusive economic zones the blasts occurred, have both concluded the pipelines were blown up deliberately, but have not said who might be responsible.

The United States and NATO have called the incident "an act of sabotage."